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-   -   Ideas for a homemade mobile antenna. (https://www.radiobanter.com/cb/32056-ideas-homemade-mobile-antenna.html)

I Am Not George June 14th 04 04:16 AM

"hypocrite Landshark" wrote:
"BP" wrote in message
...
(I Am Not George) wrote in
m:

"Twistedhed" wrote in message
ws.com...
KC8LDO, offended the nation and disgraced himself by
undermining the
death and tragedy in NYC while comparing it to his personal crusade
of cleaning up the cb channels with:

That's easy to explain. As another poster a short time back said
about
Part 95 rules "I don't care", well you see what happens when that
mind set gets applied in a different context. It is very apparent
they didn't care about human life either, including their own.
Leland C. Scott
KC8LDO
ARRL Member

Leland Scott is one of the most honest and honorable
men ever to post
in rrcb and your twisted propoganda can't ever change that.



LMAO!


Ditto!!!

Landshark


what proof do you have that Leland is other than what I say he is

BP June 14th 04 05:33 AM

(I Am Not George) wrote in
m:

"hypocrite Landshark"
wrote:
"BP" wrote in message
...
(I Am Not George) wrote in
m:

"Twistedhed" wrote in message
ws.com...
KC8LDO, offended the nation and disgraced himself by
undermining the
death and tragedy in NYC while comparing it to his personal
crusade of cleaning up the cb channels with:

That's easy to explain. As another poster a short time back said
about
Part 95 rules "I don't care", well you see what happens when that
mind set gets applied in a different context. It is very apparent
they didn't care about human life either, including their own.
Leland C. Scott
KC8LDO
ARRL Member

Leland Scott is one of the most honest and honorable
men ever to post
in rrcb and your twisted propoganda can't ever change that.



LMAO!


Ditto!!!

Landshark


what proof do you have that Leland is other than what I say he is




Look Mom, I found a google troll..

..."Get rid of it, dear.. they're disgusting, filthy vermin"


Lancer June 14th 04 12:59 PM

On 13 Jun 2004 17:16:09 -0700, (I Am Not
George) wrote:

loss because the losses are less in an open air coil.
(resistive losses, capacitive coupling losses, form loss)
Do a search on coil Q

Care to argue that point?


"The open air coil has less loss because the losses are less in an
open air coil." thats like Twisty saying "its true because I said so"
lol. Care to argue that point?


Sure, I explained why the losses are less in an open air coil,y ou
chose to ignore it. Grab a book and look up Q and see what it says.
You do know how to read don't you?

Don't bother getting back to us, your arguing just argue. I don't
have anymore time for your stupidity.

Frank Gilliland June 14th 04 01:20 PM

In [email protected], Lancer
wrote:

snip
Wrong, the coil has very little radiation. The open air coil has less
loss because the losses are less in an open air coil.
(resistive losses, capacitive coupling losses, form loss)
Do a search on coil Q

Care to argue that point?



I would. What happens when you bring a solid sheet of conductive
material close to the end of a coil? Eddy currents -- it has
tremendous losses, the Q drops like a rock, and it's inductance is
unpredictable. It's a royal bitch to design a shielded IF/RF coil or
transformer to be used for high frequencies, and shielding is almost
-never- used for power RF coils and transformers unless there is some
serious space between the inductor and shield, hence the popularity of
toroid cores for those applications. And since a bigger coil makes a
bigger field, you need much more 'free space' to maintain a high-Q.
Vertically mounting a big coil above the sheet metal of a vehicle
results in a very lossy coil.



4) A stainless steel antenna is less efficient than a copper antenna
of the same length.


not if its electrically shorter than the stainless one


Electrically shorter? You meant physically shorter. I can take a 18
foot antenna and make it electrically shorter than 9 feet while still
keeping it 18 feet long. dumbass



The difference between copper and stainless steel is not very
significant at 27 MHz. What -is- significant is that bare copper will
quickly form a layer of corrosion (visible or not) which will render
an excellent conductor useless for RF. So unless you are willing to
polish and degrease the antenna every day, I'll take the stainless.






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Lancer June 14th 04 01:23 PM

On Mon, 14 Jun 2004 05:20:37 -0700, Frank Gilliland
wrote:

In [email protected], Lancer
wrote:

snip
Wrong, the coil has very little radiation. The open air coil has less
loss because the losses are less in an open air coil.
(resistive losses, capacitive coupling losses, form loss)
Do a search on coil Q

Care to argue that point?



I would. What happens when you bring a solid sheet of conductive
material close to the end of a coil? Eddy currents -- it has
tremendous losses, the Q drops like a rock, and it's inductance is
unpredictable. It's a royal bitch to design a shielded IF/RF coil or
transformer to be used for high frequencies, and shielding is almost
-never- used for power RF coils and transformers unless there is some
serious space between the inductor and shield, hence the popularity of
toroid cores for those applications. And since a bigger coil makes a
bigger field, you need much more 'free space' to maintain a high-Q.
Vertically mounting a big coil above the sheet metal of a vehicle
results in a very lossy coil.


I would think that 4 feet would be more than enough distance.
So you would say that a large air wound coil has more loss than a
small diameter coild wound on a solid form?



Frank Gilliland June 14th 04 01:44 PM

In , Lancer
wrote:

On Mon, 14 Jun 2004 05:20:37 -0700, Frank Gilliland
wrote:

In [email protected], Lancer
wrote:

snip
Wrong, the coil has very little radiation. The open air coil has less
loss because the losses are less in an open air coil.
(resistive losses, capacitive coupling losses, form loss)
Do a search on coil Q

Care to argue that point?



I would. What happens when you bring a solid sheet of conductive
material close to the end of a coil? Eddy currents -- it has
tremendous losses, the Q drops like a rock, and it's inductance is
unpredictable. It's a royal bitch to design a shielded IF/RF coil or
transformer to be used for high frequencies, and shielding is almost
-never- used for power RF coils and transformers unless there is some
serious space between the inductor and shield, hence the popularity of
toroid cores for those applications. And since a bigger coil makes a
bigger field, you need much more 'free space' to maintain a high-Q.
Vertically mounting a big coil above the sheet metal of a vehicle
results in a very lossy coil.


I would think that 4 feet would be more than enough distance.



It would depend on the diameter of the coil. I remember there is an
equation somewhere to determine the loss, but it involves some heavy
calculus and it's too early in the morning for integrals.


So you would say that a large air wound coil has more loss than a
small diameter coild wound on a solid form?



No, not necessarily. If the wire diameter is the same, the smaller
coil might easily be more efficient due to lower DC resistance.
Distributed capacitance isn't much of an issue at 27 MHz unless you
have lots of close-wound turns, and even then it's not necessarily a
loss but a factor that affects the coil's reactance. Regardless, there
are very effective winding techniques to reduce that problem. There
are many low-loss coil form materials available, such as Teflon, some
of the better quality ceramics, and even grooved hardwood makes a
decent core at RF frequencies (however, PVC sucks above a couple
hundred kHz). There is also the issue of weather conditions that can
significantly affect an open coil regardless of whether or not the
wire is insulated -- rain/humidity, snow, air pollutants (ozone can
make a -=BIG=- difference!), etc. Even the speed of the vehicle can
have an effect on the properties of an open coil. For the sake of
consistency and longevity, a smaller coil that is sealed from the
elements (as a whole) is a far better choice for anyone serious about
the issue.






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-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Landshark June 14th 04 02:22 PM


"BP" wrote in message
...
(I Am Not George) wrote in
m:

"hypocrite Landshark"
wrote:
"BP" wrote in message
...
(I Am Not George) wrote in
m:

"Twistedhed" wrote in message
ws.com...
KC8LDO, offended the nation and disgraced himself by
undermining the
death and tragedy in NYC while comparing it to his personal
crusade of cleaning up the cb channels with:

That's easy to explain. As another poster a short time back said
about
Part 95 rules "I don't care", well you see what happens when that
mind set gets applied in a different context. It is very apparent
they didn't care about human life either, including their own.
Leland C. Scott
KC8LDO
ARRL Member

Leland Scott is one of the most honest and honorable
men ever to post
in rrcb and your twisted propoganda can't ever change that.



LMAO!

Ditto!!!

Landshark


what proof do you have that Leland is other than what I say he is




Look Mom, I found a google troll..

.."Get rid of it, dear.. they're disgusting, filthy vermin"


LOL!!! I love it. All I do is type Ditto to "LMAO"
and notice Geo calls ME a hypocrite. He should talk, right
BP. He defends Doug a known Felon, repeater jammer,
porn poster, spammer, nut case. Leland defends Doug too,
so George has no legs to stand on when calling other people
hypocrites.

Landshark


--
Treat people as if they were what
they ought to be and you will help
them become what they are capable
of becoming.



Lancer June 14th 04 03:00 PM

On Mon, 14 Jun 2004 08:14:58 -0500, itoldyouiamnotiamnotgeorge
wrote:

Lancer wrote in news:[email protected]
4ax.com:

I would think that 4 feet would be more than enough distance.
So you would say that a large air wound coil has more loss than a
small diameter coild wound on a solid form?


There are no large coil cb antennas where the coil is 4' from the vehicle
roof, they are all mounted 18" or less.


Bug Catchers aren't.. so all isn't correct.

Chris June 14th 04 03:02 PM

Replacing the lower section with pvc for flexibility. Sorry this thread is
hard to follow....too much off topic content.

Chris
"Lancer" wrote in message
news:[email protected] ...
On Sat, 12 Jun 2004 23:52:38 GMT, "Chris"
wrote:

Thanks. I just wanted to prove to myself that I could make my own antenna
and see how well it worked. There are 2 reasons for the large coil. In
comparing a few antennas of roughly equal length, the ones with large

open
coils tend to be more broad-banded. Larger materials also have less
resistive loss and more radiating are. The lower part doesn't really have

to
be 1/2' copper pipe but it was the first thing I thought of. I'm going

with
copper wire wrapped on pvc shortly.

Chris


Chris; Nice looking antenna, large open air coils are more efficient.
Some people see a large open air coil and think its all about power
handling capability. Are you planning on replacing the coil with pvc
wrapped with wire, or the lower section? If you want to beef up the
lower secton you might take a trip to a hamfest and pick up a lower
section of a Newtronics Hustler.




Lancer June 14th 04 03:24 PM

On Mon, 14 Jun 2004 14:02:15 GMT, "Chris"
wrote:

Replacing the lower section with pvc for flexibility. Sorry this thread is
hard to follow....too much off topic content.


Chris; yes there is, and for that I apologize.

PVC gets very brittle when exposed to sun or cold. You might need to
think about hooking some kind of line to it keep from losing the top
of the antenna in case it breaks.


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